question_answer

Angle between the line \[\frac{x}{a}+\frac{y}{b}=1\]and \[\frac{x}{a}-\frac{y}{b}=1\]

A)  \[2{{\tan }^{-1}}\frac{b}{a}\] 

B)  \[{{\tan }^{-1}}\frac{2ab}{{{a}^{2}}+{{b}^{2}}}\]

C)  \[{{\tan }^{-1}}\frac{{{a}^{2}}-{{b}^{2}}}{{{a}^{2}}+{{b}^{2}}}\]                 

D)  \[2{{\tan }^{-1}}\frac{a}{b}\]

E)  None of these